• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.10
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• pp.1368-1375
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• 2013

The Smart Grid, which can monitor or diagnose the power grid in real time to operate efficiently, has been pushed ahead systematically as one of alternatives to solve these issues by combining the advanced Information Communication Technology and the electrical network. Hence, the electric company which introduces smart grid technology can read remotely the electrical meter readings by means of two-way communication between the meter and the central system. This enabled the customer and the utility to take part in reasonable electrical energy utilization. AMI became one of the core foundations in realizing the Smart Grid. It is hard to test the entire process of AMI system before the full deployment because it covers the broad objects from the customer to the utility operation system and requires mass data handling and management. Therefore, we design an efficient AMI network model and a simulator for performance evaluation required to simulate the network model similar to the real environment. This tool supports to evaluate the efficiency of the AMI network equipments and deployment. Additionally, it estimates the appropriate number of deployments and the proper capabilities.

• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.361-366
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• 2016

This paper presents an arbitrary impedance transformer with unequal split, based on S- to admittance parameter conversion. When compared even/ odd- mode analysis, the parameter conversion design method constitutes a simple design method to include phase delay information and arbitrary port impedances and asymmetrical configurations. To validate this design method, we designed a 50 to $12.5{\Omega}$ impedance transformer with a 3:1 unequal power split, at an operating frequency of 1 GHz. To implement the proposed impedance transformer, the low impedance transmission lines of calculated result are fabricated by the transmission line connected shunt open stub. Good experimental performances were obtained, in full agreement with simulated results.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.140-153
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• 2005

During the tunnel construction the major failure mode can be categorized as: tunnel failure just after the tunnel excavation without support, failure after application of shotcrete and finally failure after setting the concrete lining. The failure mode just after the tunnel excavation without support, can be further classified as : bench failure, crown failure, face failure, full face failure, failure due to weak strata and failure due to overburden. Moreover the failure after application of shotcrete is classified as heading face failure, settlement of shotcrete support, local failure of shotcrete lining and invert shotcrete. To find out the major causes of tunnel collapse, the investigation was done in case of the second phase of Seoul subway construction. The investigation results depicted that the major causes of tunnel collapse were due to the weak layer of rock/fault and sudden influx of ground water from the tunnel crown. While the investigation results of the mountain road tunnels construction have shown that the major causes of tunnel failure were inadequate analysis of tunnel face mapping results, intersection of faults and limestone cavities. In this paper some recent measurement in order to mitigate such tunnel collapse are presented

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.5
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• pp.112-117
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• 2004

In this paper, in order to obtain the detailed information about lightning electromagnetic pulses, the electromagnetic pulses radiated from intracloud discharges were measured, and their characteristics and waveform parameters were analyzed statistically. The electromagnetic pulses produced by intracloud discharges are distinctly different with those by lightning return strokes. The zero-crossing times and the full pulse widths of the large bipolar electromagnetic pulses are gradually decreased as the stroke proceeds. Also, the electromagnetic pulses tend to be bipolar, with narrow and fast leader pulses superimposed on the initial half cycle. The mean numbers of leader pulses superimposed on the initial half cycle were 1.61$\pm$0.74 and 1.75$\pm$0.73 for the positive and negative polarities, respectively.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.33
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• pp.247-275
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• 2007

This paper is to propose the Direction for the institutional improvement of Financial Supply Chain Management(FSCM) Solution which are currently coming into operation under Global e-Trading Platform. The Financial Supply Chain compromise the entire trade processes and information that manage a trader's cash, Accounts payable and receivable, Risk, working capital, and so on in international trade transaction. From a buyer's perspective, this involves the full procurement-to-payment process. For the seller, it is the order-to-cash cycle. Bolero provides the party concerned a e-trade platform which conformed to these fundamental pre-requisites to underpin fully electronic trade. But this FSCM solution have failed to provide the efficient platform to effectively manage the process of Global e-Trade because it does not correspond with e-Trade environment. Therefore, present FSCM system need the institutional improvement as follows: AA) Strengthening the role of the correspondent Bank under e-Trade System, BB) Extending the function of e-Trade intermediary institution, CC) The introduction of Trade Insurance System, etc. So, by streamlining and automating these processes on an open and flexible platform, The party concerned can optimize their trade transaction and maintain better relations with their business partners

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.2
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• pp.187-200
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• 1998

This paper presents an original approach for solving short-term power scheduling in extended power system with two fuels in a unit and a limited fuel using Lagrangian relaxations. The underlying model incorporates the full set of costs and constraints including setup, production, ramping, and operational status, and takes the form of a mixed integer nonlinear control problem. Moreover, the mathematical model developed includes two fuels in a unit and a limited fuel, regulation reserve requirements of prespecified group of units. Lagrangian relaxation is used to disaggregate the model by generator into separate subproblems which are then solved with a nested dynamic program including empirical knowledges. The strength of the methodology lies partially in its ability to construct good feasible solutions from information provided by the dual. Thus, the need for branch-and-bound is eliminated. In addition, the inclusion of two fuels in a unit and a limited fuel provides new insight into the limitations of current techniques. Computational experience with the proposed algorithm indicates that Problems containing up to 23 units including 8 unit used two fuels and 24 time periods can be readily solved in reasonable times. Duality gaps of less than 4％ were achieved.

• Journal of Korean Society for Quality Management
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• v.30 no.3
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• pp.203-236
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• 2002

Environmental Performance Evaluation(EPE) is a key process of Corporate Environmental Management. This paper presents the results of an empirical survey on the status of current practices in EPE of Korean firms. Based on a corporate environmental management(CEM) model, which is initially developed by Hibbitt and Kamp-Roelands(2001) and modified in terms of EPE, the survey is peformed on the population of Korean firms, which are composed of firms certified as "environmentally friendly" by Korean government and/or certified under Is014001, and compares its results with those of Europe's. Although the relatively low response rate and some methodological limitations makes us be cautious about the interpretation, the results shows many interesting aspects of the current states of Korean firms' EPE practices. That is, the levels of EPE implementation in the environmentally-leading companies of Korea are almost the same as that of European companies, I. e., in the-final-part-of-developing-stage (3rd stage) level of the CEM model. It is also shown that as In Europe's case, Korean firms are also moving slower in external relationships than in internal control and management, are more developed in the parameters like environmental policy, Internal control, Information system, which are requirements of certification under Is014001, than in parameters like life cycle analysis and full cost accounting, which requires more research efforts, etc.orts, etc.

• Journal of Korean Society of Transportation
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• v.17 no.5
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• pp.7-18
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• 1999

This Paper focuses on analyzing the influences of Teleservice on travel behavior and trip demand based on the individual behavior model. The first step is to classify individuals into different Person groups who will follow similar behavior Patterns in terms of travel and communication. And then, the effect of Teleservice on trip demand is estimated using hypothetical scenario. The results on the ability of each person group to adapt themselves to Teleservice show that full-time housekeepers and senior citizens are more likely to be alienated. It is also found that transition probability to Teleservice is high for activities in bank or public office where simple forms of information such as data or text are exchanged. On that basis, it is estimated that in Seoul the savings on trip demand by Teleservice will be 7.6% of total daily trip generations.

• Journal of Community Nutrition
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• v.5 no.3
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• pp.173-177
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• 2003

This study was done to investigate the relationship of socioeconomic status and food intake to cognitive status of the older population. The subjects of this study consisted of 214 older persons aged 60 - 84 years. Interviews were conducted using the health-related habits and food frequency questionnaires to provide basic information for nutrition education program. We evaluated the current food consumption-pattern and cognitive status of the subjects. The results of this study were as follows： Mean age of the subjects was 69.7${\pm}$7.4 years. The average cognitive function score of the subjects was 7.9${\pm}$2.0 (full score was 10.0). Male had a higher cognitive status score than female. There was significant difference between cognitive status score and age, education level, pocket money, physical activity and family type. The subjects who had a higher cognitive status score ate more fish and meats group and milk and milk products than the subjects that had a lower cognitive status score. These results have demonstrated that various socioeconomic variables and food intake pattern affect on cognitive status with aging and suggest that proper nutrition education and adequate nutrient intake in quality and quantity are essential in maintaining cognitive status in later life.

• Journal of Pharmaceutical Investigation
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• v.41 no.6
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• pp.337-345
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• 2011

The objective of this work is to investigate the effect of chemical enhancer and current on the flux of donepezil hydrochloride (DH) through skin. Ethanol and N-methyl pyrrolidone (NMP) were used as chemical enhancers in combination with iontophoresis. We also have studied the effect of pH on flux and evaluated the role of electroosmosis. In vitro flux study was performed at $33^{\circ}C$, using side-by-side diffusion cell and full thickness hairless mouse skin. Passive flux of DH without enhancer was very small. As the concentration of enhancer increased, passive flux increased. After current application, flux increased markedly and the time to reach maximum decreased. Without enhancer, maximum flux was about 50 fold larger than that obtained without current. These results indicate that electromigration is playing a major role for the transport. As the enhancer concentration increased, flux also increased. NMP and ethanol increased not only the passive delivery, but also the iontophoretic delivery. Flux results indicate that ethanol has better ability than NMP in enhancing the transport of DH. The magnitudes of increase in flux by these enhancers indicate that there is a large synergistic effect in flux enhancement. Flux results from pH study showed that electroosmotic flow is reversed at low pH and the flux is hindered. These results provided some information on the flux enhancing ability of ethanol and NMP in combination with iontophoresis. The data also provided some mechanistic insights into the role of electromigration and electroosmosis on flux through skin.